Height-controlled InAs quantum dots by using a thin InGaAs layer

The structural and optical properties of height-controlled InAs quantum dots (QDs) have been investigated by transmission electron microscopy (TEM) and photoluminescence (PL). By depositing 1.4 nm In0.15Ga0.85As and a 1 monolayer (ML) InAs layer with different periods on 3 ML InAs QDs, the height of InAs QDs was systematically controlled with similar lateral size. In TEM images, the indication of dislocations due to the large strain, which can be easily seen in large QDs, is not observed even for the QD sample with the highest aspect ratio (height/width). The PL peak position is shifted toward the longer wavelength with an increase in the aspect ratio of QDs. As the aspect ratio is increased, the full width at half maximum in PL measured at 10 K is decreased from 71 to 34 meV indicating that the inhomogeneous broadening caused by the fluctuation in QD size, especially the height, is significantly reduced.

[1]  P. G. Piva,et al.  Manipulating the energy levels of semiconductor quantum dots , 1999 .

[2]  A. Stintz,et al.  Very low threshold current density room temperature continuous-wave lasing from a single-layer InAs quantum-dot laser , 2000, IEEE Photonics Technology Letters.

[3]  Nikolai N. Ledentsov,et al.  Excited states in self‐organized InAs/GaAs quantum dots: Theory and experiment , 1996 .

[4]  K. Nishi,et al.  A narrow photoluminescence linewidth of 21 meV at 1.35 μm from strain-reduced InAs quantum dots covered by In0.2Ga0.8As grown on GaAs substrates , 1999 .

[5]  Mikhail V. Maximov,et al.  Formation of coherent superdots using metal‐organic chemical vapor deposition , 1996 .

[6]  S. Chua,et al.  Effects of rapid thermal annealing on structure and luminescence of self-assembled InAs/GaAs quantum dots , 1998 .

[7]  M. Sugawara,et al.  Suppression of temperature sensitivity of interband emission energy in 1.3-μm-region by an InGaAs overgrowth on self-assembled InGaAs/GaAs quantum dots , 1999 .

[8]  J. Leem,et al.  Growth of Si-doped InAs quantum dots and annealing effects on size distribution , 2002 .

[9]  D. Bimberg,et al.  InAs/GaAs pyramidal quantum dots: Strain distribution, optical phonons, and electronic structure. , 1995, Physical review. B, Condensed matter.

[10]  Egorov,et al.  Direct formation of vertically coupled quantum dots in Stranski-Krastanow growth. , 1996, Physical review. B, Condensed matter.

[11]  H. Sakaki,et al.  Multidimensional quantum well laser and temperature dependence of its threshold current , 1982 .

[12]  J. Leem,et al.  Energy level control for self-assembled InAs quantum dots utilizing a thin AlAs layer , 2001 .